Travelling grates for incinerators



Aug. 3, 1965 F. S. SIMPSON TRAVELLING GRATES FOR INCINERATORS Original Filed Oct. 4. 1961 4 Sheets-Sheet l FIGJ ATTORNEYS Aug. 3, 1965 F. s. slMPsoN TRAVELLING GRATES FOR INCINERATORS Original Filed Oct. 4, 1961 4 Sheets-Sheet 2 INVENTOR. FRANK S. SIMPSON ATTORNEYS Aug. 3, 1965 F. s. SIMPSON TRAVELLING GRATES FOR INCINERATORS original Filed oct. 4, 1961 4 Sheets-Sheet 3 FIG.5.

FIG.6.

F I G. 8

INVENTOR. FRANK S. SIMPSON BY mM/away@ ATTORNEYS Aug. 3, 1965 F. s. SIMPSON 3,198,146

TRAVELLING GRATES FOR INCINERATORS Original Filed Oct. 4, 1961 4 Sheets-Sheet 4 INVENTOR. FRANK S. SIMPSON BY JMW/f. mfgay@ ATTORNEYS United States Patent O 3,195,146 T TRAVELLNG GRATE FR ENCINERA'IORS rFrank S. Simpson, Alton, iii., assigner to Iliinois Stoker 7 Claims. (Cl. 11th-40) This application is a continuation of my prior copending application Serial No. 144,482, filed October 11, 1961, now abandoned.

This invention relates to travelling grates for incinerators and the like, and more particularly to the construction of the flexible grate or apron which moves over a suitable structural support within the incinerator and actually conveys the trash as it is burned. The suitable structural support, above-mentioned, is usually a supporting framework constructed with a pair of side frames joined together top and bottom in spaced relation by cross braces. The side frames are usually located adjacent the side walls of a furnace. The interconnecting cross braces are rows of I-beains secured at opposite ends to the side frames. One row of cross braces is attached at opposite ends along the upper side of the side frames, and a similar row of I-beams similarly extends along and is attached at the lower side of the side frames. In addition, spaced apart wear rails extend parallel to the side frames. Some of these wear rails are supported by the upper side of the row of l-beams along the upper side of the side frames. Others are similarly supported on the upper side of the row of l-bearns along the lower side of the side frames. Located beyond the opposite ends of the wear rails and extending from side frame to side frame are shafts which are journalled on opposite ends in opposite side rails. Spaced sprockets are xed along each shaft so as to line up on opposite shafts at opposite ends of the machine. These members together form the structural support.

The travelling aprons, or grates, used nowadays have certain features in common. These features include drive chains trained around a sprocket at each end of the structural support. There are at least one pair of spaced chains in a travelling grate, or apron, and usually there are several pairs, but the general idea -of their interconnection with the travelling grate can be comprehended without describing travelling grates, or aprons, with more than one pair. In these structures, each link of a chain carries a bracket and the chains `are interconnected by grate bars extending from a bracket on a link on one chain to a corresponding bracket on a link on the other. The brackets on the chain links form the means for connecting each grate bar to a link of each chain. Along the lower side of each grate bar are spaced sockets containing replaceable Wear shoes. The spacing of the wear shoes matches the spacing of the wear rails at least along the upper side of the side frame so that the upper, or active run, of the grate, or apron, is supported on the rails by the shoes.

Grate bars usually are provided with opposite extending flanges along their top edges. One of these flanges is normally notched. The grate links, which are supported on the anges of the grate bars, in turn, have a depending pedestal slotted to receive the flange on the grate bar and are dropped into place through the slot and slid along the grate bar to the proper position. A special locking link closes the slot in the flange of the grate bar. These links are relatively narrow, but as long as the pitch of a drive chain, and each link is spaced slightly from another along the same grate bar. The ends of the grate link are also properly shaped to overlap at one end with the grate links on the next following grate bar so as to form a continuous grate which is articulated. Some of these 3,198,146 Patented Aug. 3, 1965 ICC links ride along the wear rails along the lower part of the side frames on the return or inactive run of the grate,

or apron.

From the above general description, it should be readily apparent that the grate bars are the key components of the machine. These members are the sole strength members to support the weight of the trash, the weight of the drive chain, and to transmit the driving force from the driving chains. Much time and effort is spent in their design and the design of their couplings, or connections, with the chains, since these parts all operate at high temperatures and are subject to all -of the stress. Continuous incinerator operation depends upon the durability of the grate bars and their connections, and even with the best designs, replacement is expected which means incinerator shutdown is required. Since shutdown decreases capacity of the machine, this is to be avoided.

The concept behind this invention is to provide a construction for a travelling grate in which the stresses imposed during operation are more equally divided rather than concentrated on certain elements, such as the grate bars.

It is another object of this invention to provide a travelling grate in which the weight of the drive mechanism is carried directly upon the supporting framework and not directly by the grate bar.

It is another object of this invention to provide a travelling apron, or grate, in which the chain drive becomes a principal load carrying structure.

It is another object of this invention to provide in a travelling grate of the apron type having a given wear rail spacing a construction in which the grate bars are inherently shorter, more rigid and, therefore, more durable.

It is still another object of this invention to provide an improved grate link for use in accomplishing the above objects of the invention.

According to this invention, a pair of drive chains are spaced to ride upon a pair of wear rails in the active run of the travelling grate. This differs from prior construction in which the drive chains were spaced to straddle a pair of rails. Not only does chain spacing dilfer, but each chain is made up of pairs of drive links side by side and connected in an articulated manner end to end to form a chain with each drive link, in turn, carrying a grate link preferably cast integral with the drive link. Each drive link also carries la bracket for connection with a grate bar, as is usual. Connected between opposite drive links in the pair of chains are grate bars with brackets at each end to join with the brackets on the drive links so that all the weight is on the wear rails of the framework, but the weight of the chains are not borne by the grate bars, nor do the grate bars have to extend beyond each wear rail. As heretofore described, each grate bar has flanges at its upper side which slidably receive a row of grate links. The surfaces of the grate links on the grate bars match up with the surface of the grate links carried by each of the drive links so that a continuous articulated grate, or apron is formed.

Other objects and advantages of this inventoin will appear from the following detailed description which is in such clear, concise and exact terms as will enable any one skilled in the art to make and use the same when taken in conjunction with the illustrations in the accompanying drawings, in which:

FIG. 1 is a top plan view of a supporting framework for a travelling grate;

FIG. 2 is a fragmentary vertical section taken on the line 2-2 of FIG. l;

FIG. 3 is a transverse vertical section of the framework shown in FIG. 1 taken on the line 3-3 of FIG. 2;

FIG. 4 is a transverse vertical section similar to FIG.

3 of a fragment of the left end of the framework showing the travelling grate mounted to move along the framework;

FIG. 5 is aview Ion a scale larger than that shown in FIG. 4 illustratingl in top Vplan the construction of a combined drive and grate link; l

FIG. 6 is a side elevational view of the link yshown in FIG. 5; Y f

FIG. 7 is a perspective view chain rollers; f

FIG. 8 is a `perspective view `illustrating a roller pin;

FIG. 9 is a perspective'view, on an enlarged scale, of the grate bar shown in FIG. 4; I

FIG. 10 is a plan View of the end grate bar shown in FIG. 4;

FIG. 11 is a side elevation of the end grate bar shown in FIG. 10;

FIG. 12 is a fragmentary plan view of a'grate key for .use on the grate bar of FIG. 9; and Y FIG. 13 is a side elevation ofthe grate key shown in FIG. 12. Y

Incinerators for the purposes herein described are large machines, supporting huge weights and subject to large stresses. They are, therefore, constructed accordingly. FIG. 1 shows a supporting framework for such a machine. This framework can be briefly described as having a pair of side frames' 1 and 2 interconnected by a plurality of cross braces, such as 3, 4, 5 and 6, 7 and 8.

illustrating one of the AIt will be understood that in order to illustrate the framel work it is necessary to compact the structure byv omitting the central framework. Consequently FIG. 1 illustrates only the opposite ends. Mounted upon the top surface of the cross braces, above described, are a plurality 'of wear rails 10, 11, 12, 13, 14 and 15. The right `hand end of side frames 1 and 2 mounts bearings 17 and 18 in Vwhich is journalled a drive shaft 20. On the shaft 20 are a plurality of sprockets 21, 22, 23, 24, 25 and 26, each of which is lined up with one of the wear rails. Shaft20 has a journal bearing 29 on the pedestal support 30 at one end and bearing 31 on a pedestal support 32 at its opposite end, and is driven through a coupling 34 from -a drive mechanism, generally indicated as 36.

At the left end of the machine is an idler shaft 39 which, in turn, mounts six sprockets in spaced relation 41 through 46, inclusive.V Journals 48 and 49 at opposite ends of the shaft 39 are slidably mounted inV the side -frames 1 and 2 and are positioned therein along the frames by adjustable means 50 and 51 which can position the journals 48 and 49, respectively, lengthwise of the machine so as to obtain the proper amount of slack, if any, in the travelling grate. The sprockets 21 through 26 and 41 through 46 each engagea drive chain which are mounted in pairs across the width of the machine. And during operation of the drive `mechanism 36, the travelling chains on the sprockets are propelled from right to left slowly moving the grate. 'I'he trash is fed to the right end of the machine, where it is supported upon the travelling grate and progressively consumed by ame as the grate moves slowly toward the left when the drive mechanism 36 is in operation.

Turning now to the illustration in FIGS. 2 and 3, the side frames 1 and 2 in turn are supported on side sills 54 and 55, respectivelyf These sills extend the entire length of the machine and serve tohold ,the supporting framework for the machine spaced from the bottom of Athe furnace. Side sill S5 also forms part of vertical side trusses 58 which are spaced at intervals along the side frame 2 and support the side plate 60 which ills the gap between the side frame 2 and the side wall of the furnace. lLikewise,'the 'side frame 1 is' supported on the. sill 54 which in turn forms part of the connection to vertical side trusses, generally Vindicated as 62. These trusses 62 are spaced along the side frame 1 at intervals and, in turn, are enclosed by plates to form an air duct 64 with an access door', or doors, such as 66.

. Y. As stated heretofore,the

sid'eframes 1 and 2'are interconnected by a series of cross braces, one ofwhich, 5, is shown in FIG. 3. VThe ,cross braces 3 through 8 are located adjacent the top Vof the side frames 1 and 2 and hold them in spaced position. rThe side frames for the framework arey usually made up of side trusses held spaced by these cross braces above described. Longitudinally the side trusses are secured by edge guide bars 68 and 69 secured along the tops of the trusses above the cross braces. Above the edge guide bars are gap bars, such as 70 and 71, secured in'position on the tops of the trusses by angle iron shaped holders 73 and 74. Intermediate the top and bottom of the side frames are longitudinally extending side bars 76 and 77 which rein- ,force the side frames.Y g

With particular referencev to FIG. 2, it will be noted .that there are still other cross braces, such as 80, 81, etc., extending between the side frames 1 and 2 and anchored to the sills 54 and 55. On top of these cross braces 80, 81, etc., are a plurality of wear rails A831-88, inclusive. One of these wear rails is visible in the sectional View ofy FIG. 2. Also visible in this view are a plurality of cross ducts 90, 91y and 92 to join with and communicate with the air duct 64.

The above described supporting framework'is adapted to accommodate a travelling grate, or apron, constructed 1in the manner hereinafter described. In the fragmentary sectional vieWof'FIG. 4, the Wear rails 10 and 11 support rollers 95 of drive chains 96 and 97, respectively, both of whichare constructed of links 120 of the same shape and size and will serve as examples for the construction used uniformly throughout the travelling grate. The links 120 of the drive chains 96 and 97 are all `alike and are best illustrated in FIGS. 5, 6, 7 and 8. Turning now to these particular gures,. each of the Vlinks 120 is composedfof drive bars 100 and 101, such as shown in FIGS.. 5 and '6. Since each of the drive barsis the same, a description of one 'will serve for both. Drive vbar has a boss 104 at its left end provided with a bearingV 105. At its right end is a boss 106 .with a bearing 107. Boss 106 has a transverse hole 108 to receive a locking pin.V On the side of the drive bar 100 is a boss 110 with a pair of spaced tapped holes 111 and v112 which together form half of a connection to av likeconnection on the end of a grate bar. Upstanding web 113 on the upper edge of drive bar 100 supports thereon a cover part having a rounded, or arcuate, portion 114 which will be accommodated within the arcu- 'ate portion 115 of the web 113 of the next adjacent drive, or grate, link. rOpposite drive bar 101 is constructed in the same manner as drive bar 100, and preferablythe cover part and drive bars withsupporting webs 113 are cast as integral units to form a box-like structurewhich acts as the foundation upon which the other parts of the travelling grate (at that longitudinal increment) are rigidly mounted and transported.

Successive links 120, in each chain, are articulated togetherby pins which project throughv the bearings and 107 of connected links. Pins 122,y when in place, also stiiren and complete the. box-like mounting structure 120. Pin 122 also supports a roller 95 which has a bearing` surface 126 to rotatably mountthe roller 9,5 on the round' or cylindrical pin 122. Roller 95 is accommodated between rthe ends of the drive bars 100 and 101. If desired, one or more of the rollers 95 (preferably that which rides upon rails such as 12 or 13 at or near the middleV of the travelling grate) mayl be equipped 'with anges which engage the sides of the rail or rails thereby toflmit sidewise movement of the travelling grate. ,i Y

` The drivebars 100 and 101, in turn, supportthe grate bars 1 2`8connected between corresponding Vlinks of the different drive chains 96 and 97. There are, of course, grate bars between each'pair of links of the drive chains, one for each pair across the travelling grate. Turning now to FIGS. 9 and 10, the grate bars 128 are sections of lI-beams with top llanges 129 and bottom ilanges 130 interconnected by webs 131. The top flange is notched at 133 for a purpose which will be later described. Secured to the opposite ends of the grate bars 128 are plates 134 and 135. Plate 134 has a pair of holes 135 and 137 which match up with the holes 111 and 112 in the side of each drive link. Similarly plate 135 has a pair of spaced holes 138 and 139 which will also match with the holes 111 and 112 in the drive links. Thus, plates 134 and 135 form the other half of the connection between a grate bar and a grate link. Suitable bolts secure the connection together. Each grate link at the ends of the travelling grate also supports an end grate member cover link, such as 140 shown in FIGS. 4 and ll. The end grate members 140 are all constructed alike and a description of one will serve for all. On the member 14@ is a boss 142 with spaced holes 143 and 144. This boss is part of a vertical web 145 supporting a portion with a plane surface, such as 146. The surface 146 continues toward the rear of the link and merges into an arcuate surface 147 which is received within the concavity 14S in the web of the next adjacent member. The boss 142 forms one-half of a connection with the grate link 120 which mounts the other half. The two are secured together by suitable studs projecting through the apertures, or spaced holes, 143 and 144 and threaded into the holes 111 and 112. With reference to FIG. 4, the end grate bar 140 extends beneath the gap bars 71) and 71 at the opposite sides of the travelling grate.

Supported along the top of each of the grate bars 128 are a plurality of grate keys, generally indicated as 150, these are shown in detail in FIGS. 12 and 13. Each grate key has a vertical web 151 supporting a dat upper surface 152 which merges into an arcuate trailing edge 153 adapted to be received within the arcuate portion 154 of the web 151 of an adjacent key. Protruding from one side of the web 151 is a boss 156 open at the bottom and having opposed slots 157 and 158. As will be seen in FIG. 2, the upper surface 152 of each of the grate keys 150 projects in the same direction from the vertical web as the boss o and as a matter of fact overhangs the boss by a considerable amount. These grate keys are mounted on the grate bar by hooking the slot 153 over one edge of the flange 129 and dropping the other edge of the slot 157 through the slot 153 of the grate bar. The grate keys are then slid along the grate bar to their proper positions so as to make a substantially continuous grate surface from one end of the grate bar 128 to the other. A special type of locking key 160 drops onto the grate bar last and prevents removal, or shifting, position between the other grate keys 151). The construction of such locking keys is well understood in the art and will not be described here.

Each of the drive links 96, 97, etc., see FIG. 1l, are parts of continuous chains built up in the manner described to form a travelling grate. Each separate chain is trained over its own pair of sprockets provided at opposite ends of the supporting framework. Each link of each chain supports its own grate surface, or grate link, as well as one end of -a grate bar which in turn supports a series of grate links so as to form a travelling grate surface between the sets lof sprockets at opposite ends of the machine. The drive links are supported at opposite ends by rollers 95 in engagement with the wear rails 1i), 11, etc., across the width of the travelling grate from one edge to the other so that the weight of the drive links forming the drive chains are directly supported on the supporting framework through the wear rails and not supported by the grate bars as in the past. In the present machine, grate bars are relieved of a great deal of the stresses usually carried and their duty is consequently much lighter so as to lend durability to the structure. Throughout the entire active run, the Weight of the drive chains is directly upon the wear rails. On the inactive run of the travelling grate, the top surfaces of the grate links of the chains travel along the return yrails 153-88, inclusive, see FiG. 3, thus, placing the wear and the friction load directly on the driving part of the travelling grate rather than upon the driven part.

Changes in and modifications of the construction described may be made without departing from the spirit of my invention or sacrificing its advantages.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In a travelling grate for an incinerator or the like having (a) a supporting framework including a pair of spaced side frames held spaced by rows of cross braces, (b) a plurality of spaced rails extending in the direction of said side frames and supported therebetween by said cross members, (c) a plurality of pairs of sprockets, the pairs being aligned respectively with said rails, and (d) a plurality `of endless chains each traversing a different pair of sprockets and supporting between them the several components of the grate, the improvement which comprises,

(1) said endless chains comprising articulated links of integral box-like structure, each including (i) a cover part having a longitudinal dimension parallel with said rails and a lateral dimension parallel with said cross members,

(ii) a pair of longitudinally extending drive bars depending from said cover part in laterally spaced relation to each other and each drive bar having means at each longitudinal extremity thereof for articulating it with a longitudinally adjacent drive bar,

(2) a grate bar connected between laterally aligned links of different endless chains,

(3) means for connecting said grate bars to said links with the uppermost surface of the grate bars below the level of the cover part of said links,

(4) grate keys mounted on said uppermost surface of said grate bar and together forming a surface in substantial continuity with the cover part of said links, said grate bars and said grate keys being interlocked by a raceway which admits of movement of the keys relative to the bars in the direction lengthwise of the bars but prevents relative movement between a key and its associated bar in other directions, and

(5) a locking key for preventing the escape of said grate keys from said raceway.

2. The combination of claim 1 in which a roller is mounted between the drive bars of said links in position both to be engaged by the sprockets and to ride upon the rail which is aligned therewith.

3. The combination of claim 2 where the covers of said links overhang the rollers.

4. In an endless travelling grate having a plurality of spaced parallel series of drive links, articulating pins connecting each drive link to its leading and trailing neighbors in the same series, said articulating pins extending horizontally normal to the direction of travel of said endless grate, a supporting rail for each series of articulated drive links, grate bars extending laterally between and interconnccting drive links in different series, and bearing members between said drive links and the supporting rail for the corresponding series of drive links, said bearing members being mounted upon said articulating pins, said drive links comprising an integral casting including a cover part and a pair of drive 'oars depending from said cover part, said drive hars being:

(a) laterally spaced from each other a distance suilicient to accommodate a bearing member between them,

(b) provided at each end with an aperture for the reception of an articulating pin, the apertures in one drive bar being aligned with the apertures in the other drive bar; and

(c) provided with means spaced from said apertures for connecting a grate bar thereto.

5. The link of claim 4 wherein the apertured ends of each drive bar are laterally offset from each other by an amount at least equal to the lateral dimension of the drive bar adjacent said apertures.

` 6. The combination with the link of claim 4 of a bearing member consisting of a roller mounted upon anarticu- 7.' The combination of claim4 wherein the cover part overhangs the roller.

References Cited by the Examiner UNITED STATES PATENTS v2,804,834 9/57 Rivers V110-40 `2,936,725 `5/60 Blundin et al. 110-40 l a FOREIGN PATENTS 403,449 9/09 France.

674,075 6/52 Great Britain.

JAMES W. WESTHAYEK'Prz'may Examiner. KENNETH SPRAGUE, Examiner. 

1. IN A TRAVELLING GRATE FOR AN INCINERATOR OR THE LIKE HAVING (A) A SUPPORTING FRAMEWORK INCLUDING A PAIR OF SPACED SIDE FRAMES HELD SPACED BY ROWS OF CROSS BRACES, (B) A PLURALITY OF SPACED RAILS EXTENDING IN THE DIRECTION OF SAID SIDE FRAMES AND SUPPORTED THEREBETWEEN BY SAID CROSS MEMBERS, (C) A PLURALITY OF PAIRS OF SPROCKETS, THE PAIRS BEING ALIGNED RESPECTIVELY WITH SAID RAILS, AND (D) A PLURALITY OF ENDLESS CHAINS EACH TRAVERSING A DIFFERENT PAIR OF SPROCKETS AND SUPPORTING BETWEEN THEM THE SEVERAL COMPONENTS OF THE GRATE, THE IMPROVEMENT WHICH COMPRISES, (1) SAID ENDLESS CHAINS COMPRISING ARTICULATED LINKS OF INTEGRAL BOX-LIKE STRUCTURE, EACH INCLUDING (I) A COVER PART HAVING A LONGITUDINAL DIMENSION PARALLEL WITH SAID RAILS AND A LATERAL DIMENSION PARALLEL WITH SAID CROSS MEMBERS, (II) A PAIR OF LONGITUDINALLY EXTENDING DRIVE BARS DEPENDING FROM SAID COVER PART IN LATERALLY SPACED RELATION TO EACH OTHER AND EACH DRIVE BAR HAVING MEANS AT EACH LONGITUDINALLY EXTREMITY THEREOF FOR ARTICULATING IT WITH A LONGITUDINALLY ADJACENT DRIVE BAR, (2) A GRATE BAR CONNECTED BETWEEN LATERALLY ALIGNED LINKS OF DIFFERENT ENDLESS CHAINS, (3) MEANS FOR CONNECTING SAID GRATE BARS TO SAID LINKS WITH THE UPPERMOST SURFACE OF THE GRATE BARS BELOW THE LEVEL OF THE COVER PART OF SAID LINKS, (4) GRATE KEYS MOUNTED ON SAID UPPERMOST SURFACE OF SAID GRATE BAR AND TOGETHER FORMING A SURFACE IN SUBSTANTIAL CONTINUITY WITH THE COVER PART OF SAID LINKS, SAID GRATE BARS AND SAID GRATE KEYS BEING INTERLOCKED BY A RACEWAY WHICH ADMITS OF MOVEMENT OF THE KEYS RELATIVE TO THE BARS IN THE DIRECTION LENGTHWISE OF THE BARS BUT PREVENTS RELATIVE MOVEMENT BETWEEN A KEY AND ITS ASSOCIATED BAR IN OTHER DIRECTIONS, AND (5) A LOCKING KEY FOR PREVENTING THE ESCAPE OF SAID GRATE KEYS FROM SAID RACEWAY. 